William c



(No Model.)

. W. G. TURNBULL.

TELEPHONE.

Patented June 22, 1886.

WITNESSES S INVENTOR;

Lu 6? x Byfiz's .dttorne M (Z-WM N. PETERS, mwum n m wnhin m 0/0,

UNITED STATES PATENT OFFICE.

WILLIAM C. TURNBULL, OF BALTIMORE, MARYLAND.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 344,067, dated June 22,1886.

Application filed April 16, 1886.

, T all whom it may concern:

Be it known that I, WILLIAM-C. TURNBULL, of Baltimore, Maryland, haveinvented certain new and useful Improvements in Speaking- Telephones, ofwhich the followingis a specification.

The primary object of my invention is to construct a receiving-telephonefor use in con nection with a variable-contact transmitter, althoughtheinstrument may also be constructed for use as a magneto transmitteror receiver.

The peculiarities of structure will appear from the following specificdescription.

In the accompanying drawings, Figure 1 is a view in central section;Fig. 2, aview of the support with the flat tube removed, and Fig. 3 afront view showing the support with the flat tube in place.

In an application for Letters Patent filed by me February 23, 1886, No.192,916, I have shown a vibrating plate held at two edges only andmaintained under tension. In my present invention I prefer to make useof a strained plate similarly supported.

A represents a flattened tube of soft iron or other inductive material,which is mounted upon a suitable support, B, and is strained or heldunder tension thereon, preferably by means of a pin, b, which is drivenbetween the edge of the support B and one side of the flat tube. Thesupport B upon one side is turned out or cut away, so as to form aresonatingchainber between it and the plate a, or, in other words, oneof the sides of the strained fiat tube. The support B is formed with acentral aperture at the center, and this resonating-chamber and theopposite side of the Serial No. 199,133. (No model.)

arranged in suitablejuxtaposition to the plate a, while the aperture 0will of course in practice be arranged in proper relation to a suit ableear or mouth piece. Vith an instrument ticulation and good volume.

Of course, the structure may be used in a magneto-instrument or in anordinary varia hie-resistance receiver.

I am aware of the construction shown in the patent of Eiehmeyer, No.210,929, and I do not, therefore, claim such organization.

I claim as my-invention 1. The combination of the strained vibratingrectangular metallic plate a, supported at two opposite edges instraight parallel lines and free to vibrate between said supports, theelectro-magnet, the resonating-chamber, and an aperture leading from thercson ating-chamher and located centrally with reference to the chamberand vibrating plate.

2. The combination of the magnet, the fiat tube having one side formedwith an aperture, and the support B, having a corresponding aperture. I

3. The combination, in a speaking-telephone, of the fiat tube, thesupport B, and the straining or tension pin. V

In testimony whereof I have hereunto subscribed my name.

\VILLIAM G. .TUBNBULL;

thus constructed I obtain a clear,distinet ar-

